A list of seemingly valid alarm tags not used on graphics can be found in the Module Block Map index accessible via the Block Map link in each Module Index.
This report list tags which are defined in the database, but not used on graphics, but which nevertheless probably have a valid reason to be in the database because they seem to be useful alarm tags. It is not necessary for alarm tags to be used on graphics in order to be functional. The "unused" description merely means that they are not found on graphics, not that they are not used at all.
DBDOC uses several heuristics to determine if a tag is probably a useful active alarm tag:
For tags on digital values:
- If the tag is not in alarm group 0 (alarm group 0 suppresses alarming), and has spec 2 set to 0 or 1 (meaning alarms are expected on status changes), then this tag is considered to be a useful active alarm tag, and DBDOC puts it in the List of Unused Alarm Tags index. This tag should not be removed from the database, because it seems that it is useful.
- Tags that are in group 0, and tags not in group 0 but that have spec 2 set to 2 (meaning suppress the alarm), show up in the Module: List of Unused Tags index, and are candidates for removal from the database.
For tags on analog values
- If the tag is not in alarm group 0 (alarm group 0 suppresses alarming), and has "reasonable" high/low threshhold values (compare to the zero and span), then this tag is considered to be a useful active alarm tag, and shows up in the List of Unused Alarm Tags index. This tag should not be removed from the database, because it seems that it is useful.
- Large positive or negative high/low threshholds compared to the expected range of a value can be used to disable the alarm. Tags that are in group 0, or or not in group 0, but appear to have "unreasonable" disabling high/low limits, and are also not found on graphics, show up in the Module: List of Unused Tags index, and are candidates for removal from the database.
See Also